The present invention relates to cartridges containing disks and signal recording or reproduction devices for the disk.
FIG. 10 is a perspective view of a conventional cartridge 6 [see JP-B No. 7-36261(1995)]. The cartridge 6 comprises a flat shell 9 containing a disk 60. The shell 6 has a side face provided with a slit 5. In the vicinity of the slit 5, the shell 9 has an aperture 63 formed in the upper wall thereof for exposing the disk 60. A shutter 61 is provided over the aperture 63 and the slit 5. A fitting hole 62 is formed in a side wall of the shutter 61. The shutter 61 is held closed by a lock claw (not shown) within the shell 9.
The cartridge 6 is inserted into a holder 2 pivoted to a chassis 1. Provided inside the holder 2 is a tooth 31 movable into the slit 5 and a spring piece 37 fittable into the fitting hole 62 in the shutter 61. The tooth 31 has an inner end positioned inwardly of the spring piece 37. When the cartridge 6 is inserted into the holder 2, the shutter 61 moves past the spring piece 37 and comes into contact with one end of the tooth 31. The tooth 31 releases the lock claw from the shutter and pushes the shutter 61 open. When the holder 2 is lowered toward the chassis 1 in this state, signals can be recorded or reproduced. In the following description, the direction in which the cartridge 6 is inserted into the holder 2 will be referred to as the xe2x80x9cfront,xe2x80x9d and the opposite direction as the xe2x80x9crear.xe2x80x9d
FIG. 11 is a view in section of the holder 2 with the cartridge 6 inserted therein as the holder is seen from the direction of arrow A in FIG. 10. When the cartridge 6 is to be unloaded from the state shown in FIG. 11, the cartridge 6 is manually pulled out of the holder 2 in a raised state. Since the spring piece 37 is fitting to the shutter 61, the shutter 61 is closed when the cartridge 6 is pulled out. When the cartridge 6 is further pulled out with the shutter 61 closed, the shutter 61 is released from the spring piece 37 fitting thereto, and the cartridge 6 is unloaded from the holder.
FIG. 12 is a side elevation showing the levels of the slit 5 of the cartridge 6, the spring piece 37 and the tooth 31. For convenience of description, the tooth 31 is shown as brought closer to the spring piece 37. The fitting hole 62 of the shutter 61 is positioned at the approximate midportion of thickness of the cartridge 6, and the spring piece 37 is positioned at a level corresponding to the hole 62. The slit 5 is positioned slightly upwardly of the approximate midportion of thickness of the cartridge 6, while the tooth 31 is positioned at a level corresponding to the slit 5. The slit 5 is positioned as shifted from the approximate midportion of thickness of the cartridge 6, so that when the cartridge 6 is inserted as turned upside down in error, the tooth 31 fails to fit into the slit 5. This obviates the likelihood that the cartridge 6 will be erroneously inserted as turned upside down.
The slit 5 comprises a horizontal groove 51 extending forward, and a guide groove 50 continuously extending from the front end of the horizontal groove 51 and enlarging toward the front. The provision of the guide groove 50 renders the tooth 31 fittable into the slit 5 easily. The lower end of the spring piece 37 is positioned downwardly of the lower edge of the horizontal grooved portion 51, such that when the cartridge 6 is inserted toward the spring piece 37, the spring piece 37 moves as opposed to the lower side edge of the horizontal grooved portion 51.
However, the construction described above has the following problem to be solved.
It is likely that the cartridge 6 will be inserted into the holder 2 while backlashing upward and downward. The spring piece 37 is then likely to move into the slit 5 through the guide groove 50 as if wedging into the guide groove 50 of the slit 5, possibly making the cartridge 6 unable to further move into the holder.
This problem may be solved by decreasing the size of the front opening of the guide groove 50, whereas this conversely makes it difficult for the tooth 31 to enter the slit 5.
While conducting studies on countermeasures against this problem, the present applicant directed attention to the fact that when the cartridge 6 is inserted into the holder 2 while allowing the cartridge to backlash up and down, both the spring piece 37 and the tooth 31 enter the slit 5 through the front opening of the guide groove 50. In other words, the applicant noticed that if the spring piece 37 comes into contact with the upper or lower end of the horizontal grooved portion 51 at the side portion of the cartridge 6 without fitting into the guide groove 50 even if the cartridge 6 backlashes up and down, the spring piece 37 encounters difficulty in entering the slit 5 since the horizontal groove 51 has a smaller width than the front opening of the guide groove 50.
An object of the present invention is to make it difficult for the spring piece to enter the slit by a simple construction.
A shell 9 has a corner in the vicinity of a slit 5 and providing a contact face 90. The slit 5 is provided at a front end portion thereof with a guide groove 50 positioned in the contact face 90 and enlarging toward the front.
The contact face 90 is in the form of a circular arc or slope and so shaped that the path of movement thereof intersects a spring piece 37 at a location A which is positioned rearwardly of a position B where the path of movement intersects the inner end of a tooth 31.